One image-forming device known in the art is a horizontal tandem-type color printer provided with a plurality of photosensitive drums that are arranged parallel to each other and juxtaposed horizontally (hereinafter called the “juxtaposing direction”), and a plurality of developing cartridges for respectively supplying developer to the photosensitive drums.
Of these types of color printers, a proposal has been provided for a printer having a support frame that integrally supports a plurality of photosensitive drums and a plurality of developing cartridges. The support frame can be moved with respect to the juxtaposed direction between an accommodated position and a withdrawn position. The printer also includes an intermediate transfer belt that contacts the photosensitive drums when the support frame is disposed in the accommodated position. Each developing cartridge includes a developing roller that contacts a corresponding photosensitive drum, and a toner-accommodating chamber for accommodating toner to be supplied onto the developing roller. The developing cartridges are detachably supported in the support frame and can be mounted therein and removed therefrom with respect to an axial direction of the developing rollers while the support frame is disposed in the withdrawn position.